Condenser evaporator and cooling device

ABSTRACT

The invention provides a compact and inexpensive cooling device with high heat transfer efficiency and with easy maintenance. The cooling device includes a condenser ( 10 ), an evaporator ( 20 ), and a pair of refrigerant flow passages between them. In each of the condenser ( 10 ) and the evaporator ( 20 ), through holes ( 11   a   , 21   a ) are formed in parallel with each other. The condenser ( 10 ) is formed in a cylindrical shape and installed around the cooling head of the refrigerator by a clamp ( 14 ). The evaporator ( 20 ) is installed the outside. The refrigerant is liquefied in the condenser ( 10 ) by releasing its heat, flows down into the evaporator ( 20 ) through the flow passage and is vaporized in the evaporator ( 20 ) by absorbing heat from the outside. The vaporized refrigerator flows up and returns into the condenser ( 10 ).

BACKGROUND OF THE INVENTION

[0001] The present invention relates to a cooling device, moreparticularly to a condenser that rejects heat of a refrigerant to theheat absorption portion of an exterior refrigerator and liquefies it, anevaporator that absorbs heat from an object to be cooled and vaporizesthe refrigerant, and a cooling device including the condenser and theevaporator.

DESCRIPTION OF THE RELATED ART

[0002] Various types of cooling devices have been proposed to coolspaces or objects. In some applications, however, it may be difficult toinstall the heat absorption portion of the cooling devices in proximityto those spaces or objects. An icebox used in a car has a difficulty todirectly attach the heat absorption portion thereon due to thelimitation of available spaces interior of the car. Warming of the carinterior by the heat radiation of the cooling device has to be avoidedas well. In cooling the CPU of the computer where many associated partsare arranged in narrow spaces, installation of cooling devices near theCPU is further difficult.

[0003] In order to resolve such difficulties in installation of coolingdevices, a cooling means, having the following configuration and shownin FIG. 10, has been proposed. An exterior refrigerator is spaced apartfrom an object 92 to be cooled, and a refrigerant are circulated betweenthe heat absorption portion 91 of the exterior refrigerator and theobject 92 to be cooled. That is, the refrigerant is cooled at a heatreject portion 51 attached to the heat absorption portion 91 of theexterior refrigerator, then being introduced through a passage 55 to aheat absorption portion 52 provided in contact with the object 92 to becooled, thereby the object 92 is cooled. The refrigerant warmed at theheat absorption portion 52 is circulated back to the heat reject portion51 through a passage 56.

[0004] In the above cooling means, the heat reject portion 51 isthermally coupled with the heat absorption portion 91 of the exteriorrefrigerator in such a configuration that a refrigerant pipe is woundaround or laid along the heat absorption portion 91 of the exteriorrefrigerator. The heat absorption portion 52 is thermally coupled withthe object 92 in the same configuration as well.

[0005] The above cooling means, by its nature, needs enhancing eitherthe heat transfer performance between the heat absorption portion 91 ofthe exterior refrigerator and the heat reject portion 51 or that betweenthe object 92 to be cooled and the heat absorption portion 52 in orderto improve its cooling efficiency.

[0006] Further, size reduction of the cooling means is required as well.In the application of the cooling means to the computer CPU or the like,in which as the object 92 to be cooled is extremely small with only asmall amount of heat generated, the exterior refrigerator is small, theheat reject portion 51 fixed to the heat absorption portion 91 thereofhas to be small, and so does the heat absorption portion 52 fixed to theobject 92. In summary, both the size reduction of either the heat rejectportion 51 or the heat absorption portion 52 and the increases of theirheat transfer performance are important.

[0007] The cooling means also requires simple and easy means forattaching the heat reject portion 51 to the heat absorption portion 91of the exterior refrigerator or detaching it therefrom and that forattaching the heat absorption portion 52 to the object 92 to be cooledor detaching it therefrom without sacrificing its heat transferperformance.

[0008] Accordingly, an object of the present invention is to provide acompact condenser and evaporator with an efficient heat transferperformance and with easy maintenance and to provide a cooling devicehaving including the compact condenser and evaporator.

SUMMARY OF THE INVENTION

[0009] In accordance with a first aspect of the present invention, acondenser that condenses a refrigerant gas by rejecting heat of the gasto a predetermined column-like shaped heat absorption portion of anexterior cooling device includes a condensing portion, an inlet portion,and an outlet portion. The condensing portion is formed of a flat plateshaped so as to surround the entire periphery of the column-like shapedheat absorption portion. The condensing portion further has a pluralityof through holes formed along the circumferential direction thereof andarranged in parallel with each other. The inlet and outlet portionsbeing hollow tubes have a closed end and an open end respectively. Theinlet portion is connected to one end face of the condensing portionthat is perpendicular to the circumferential direction of the condensingportion. The inlet portion communicates with all of the through holes.The outlet portion is connected to the other end face of the condensingportion that is perpendicular to the circumferential direction of thecondensing portion. The outlet portion communicates with all of thethrough holes. The open end of the inlet portion is connected to aninflow passage of the refrigerant. The open end of the outlet portion isconnected to an outflow passage of the refrigerant which section area issmaller than that of the inflow passage. The condensing portion isinserted into and fixed to the column-like shaped heat absorptionportion.

[0010] The end faces of the condensing portion that are perpendicular tothe circumference thereof not only means those formed by dividing theentire circumference thereof into two semicircles, but also means thoseformed by cutting the condensing portion at one portion on itscircumference.

[0011] By employing the above-described configuration, the presentinvention provides the following functions and effects. Namely, iftemperature of a refrigerant is merely lowered at a heat-rejectingportion, no more than the amount of heat is rejected which correspondsto the multiplier of the heat capacity of the refrigerant by thetemperature differentials of the refrigerant. On the other hand, thepresent invention enables to reject a larger amount of heat bycondensing a refrigerant vapor at a condensing portion, to achieve ahighly effective heat transfer. Moreover, the condensing portion isconfigured so that the entire periphery of the column-like shaped heatabsorption portion is surrounded with a flat plate having a number ofnarrow through holes arranged. Accordingly, while the heat transfer areacan be larger, the heat absorption portion and the heat condensingportion attached thereto can be smaller.

[0012] Further, as the condensing portion is attached only by insertingit to the column-like shaped heat absorption portion, attachment anddetachment can be easier, and assembling and maintenance workability isimproved without impairing its heat transfer performance.

[0013] The section area of the outflow passage of the refrigerant issmaller than that of the inflow passage, because as the volume of thevaporized refrigerant drastically decreases by condensing, smallersection area is enough for the outflow passage.

[0014] In accordance with a second aspect of the present invention, thecondenser in the first aspect thereof is further provided with a clampformed so as to surround the condensing portion, inserted into thecolumn-like shaped heat absorption portion, and attached to it byfastening the clamp.

[0015] With employing the above-described configuration, the presentinvention provides the following functions and effects. When thecondensing portion is inserted into the column-like shaped heatabsorption portion, if either the outer periphery of the heat absorbingportion or the inner circumference of the condensing portion is notprecisely finished, they has to loosely contact with each other, causingpoorer heat transfer performances. In the present invention, however, inwhich the outer circumference of the condensing portion is fastened tothe heat absorption portion by means of a clamp, they closely contactswith each other, enabling easy attachment and detachment withoutreducing its heat transfer performance. Consequently, the inventionimproves workability of assembly, maintenance or inspection withoutimpairing heat transfer performance.

[0016] In accordance with a third aspect of the present invention, thecondensing portion either in the first or second aspect thereof iscomprised of a plurality of hollow tubes that are arranged in parallelwith each other.

[0017] In this configuration, nearly equal functions and effects asmentioned above can be achieved at a lower cost.

[0018] In accordance with a fourth aspect of the present invention, anevaporator that vaporizes a liquid refrigerant by absorbing heat from anexterior heat source includes a vaporizing portion, an inlet portion,and an outlet portion. The vaporizing portion is formed of a flat plateprovided with a plurality of through holes arranged in parallel witheach other. The inlet and outlet portions being hollow tubes have aclosed end and an open end respectively. The inlet portion is connectedto one end portion of the vaporizing portion at its outercircumferential surface. The inlet portion further communicates with allof the through holes. The outlet portion is connected to the other endportion of the vaporizing portion at its outer circumferential surface.The outlet portion further communicates with all of the through holes.The open end of the inlet portion is connected to an inflow passage ofthe refrigerant. The open end of the outlet portion is connected to anoutflow passage of the refrigerant which section area is larger thanthat of the inflow passage. The vaporizing portion is attached to theexterior heat source.

[0019] The above-mentioned configuration of the present inventionprovides following effects. Generally, in raising the temperature of acold liquid refrigerant at a cooling portion, no less than the amount ofheat is absorbed which corresponds to the multiplier of the heatcapacity of the liquid refrigerant by the temperature differencethereof. On the other hand, in the present invention, if the liquidrefrigerant is vaporized at an evaporator, an amount of heat equivalentto the vaporization heat thereof may be absorbed, thereby higher heattransfer performance is achieved. Further, as the heat transfer area ofthe evaporator is enlarged by employing a flat plate with a number ofthrough holes disposed therein in parallel with each other, theevaporator attached to the exterior heat source can be reduced in size.This configuration of the present invention is especially effective forhighly integrated small objects such as the CPUs for computer.

[0020] Further, the evaporator can be easily attached to or detachedfrom objects to be cooled by means of nuts or clamps, assembly,maintenance and inspection thereof can be improved without impairing itsheat transfer performance.

[0021] Furthermore, in the evaporator of the present invention, thesection area of the outflow passage of the refrigerant is larger thanthat of the inflow passage, as volume of the refrigerant increasesgreatly by the vaporization.

[0022] In accordance with a fifth aspect of the present invention, anevaporator that vaporizes a liquid refrigerant by absorbing heat fromair passing through includes a vaporizing portion, an inlet portion, anoutlet portion and a fin. The vaporizing portion is formed of a flatplate provided with a plurality of through holes arranged in parallelwith each other. The vaporizing portion is bended to insert a spacehaving predetermined height and length between it.

[0023] The fin is inserted into the space crossing with the through holedirection. The inlet and outlet portions being hollow tubes have aclosed end and an open end respectively. The inlet portion is connectedto one lower end portion of the vaporizing portion at its outercircumferential surface. The inlet portion further communicates with allof the through holes. The outlet portion is connected to the otherhigher end portion of the vaporizing portion at its outercircumferential surface. The outlet portion further communicates withall of the through holes. The open end of the inlet portion is connectedto an inflow passage of the refrigerant. The open end of the outletportion is connected to an outflow passage of the refrigerant whichsection area is larger than that of the inflow passage.

[0024] The above-mentioned configuration of the present inventionprovides following effects. The heat transfer area of the evaporator canbe enlarged by employing a flat plate with a number of through holes.Further, the evaporator with long length can be small sized by bendingit. And further more, the heat transfer area with hot air passingthrough can be increased by installing the fin between the bendedvaporizing portion. Consequently, the evaporator can be small sized,while the heat transfer aria with the refrigerant and the hot airpassing through can be increased.

[0025] In accordance with a sixth aspect of the present invention, thevaporizing portion either in the fourth or fifth aspect thereof isformed of a plurality of hollow tubes arranged in parallel with eachother.

[0026] By employing above-mentioned configuration of the presentinvention, same effects as previously mentioned can be achieved at alower cost.

[0027] In accordance with a seventh aspect of the present invention,there is provided a cooling device comprising the condenser either inthe first, second, or third aspect thereof and the evaporator either inthe fourth, fifth or sixth aspect thereof, wherein the outflow passageof the condenser is connected to the inflow passage of the evaporator,and the inflow passage of the condenser is connected to the outflowpassage of the evaporator.

[0028] The above-mentioned configuration of the present invention canreduce the size of the device, enhance cooling efficiency, and improveworkability of assembly, maintenance or inspection.

BRIEF DESCRIPTION OF THE DRAWINGS

[0029]FIG. 1 is a schematic side view of the condenser according to thepresent invention.

[0030]FIG. 2 is a schematic front view of the condenser according to thepresent invention.

[0031]FIG. 3 is a schematic enlarged view of the cooling deviceaccording to the present invention.

[0032]FIG. 4 is a schematic enlarged perspective view of inlet portionsand outlet portions of the cooling device according to the presentinvention.

[0033]FIG. 5 is a schematic plan view of the evaporator according to thepresent invention.

[0034]FIG. 6 is a schematic front view of the evaporator according tothe present invention.

[0035]FIG. 7 is a schematic perspective view of the evaporator with thethin fin between the bended vaporization portion.

[0036]FIG. 8 is a schematic arrangement view of hollow tubes used forthe condenser or the evaporator according to the present invention.

[0037]FIG. 9 is a schematic view of a driving pump of refrigerantaccording to the present invention.

[0038]FIG. 10 is a schematic view of a conventional cooling means.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0039]FIGS. 1 and 2 shows a condenser 10, which condenses a vaporizedrefrigerant by rejecting heat to a cylindrical heat absorption portion19 that comprises an exterior cooling device. The condenser 10 iscomprised of a condensing portion 11, an inlet portion 12, an outletportion 13, and a clamp 14. As the refrigerant, suitable material ofwhich phase changes from a gas to a liquid state, is chosen, for examplelike carbon dioxide. Depending on the temperature of the heat absorptionportion 19 and the like, appropriate refrigerant and appropriate fillingpressures are selected. The condensing portion 11 is comprised of a flatplate of aluminum formed so as to surround the outer periphery of thecylindrical heat absorption portion 19.

[0040] As shown in FIG. 3, the flat plate 11 is provided so that anumber of through holes 11 a are disposed in parallel with each other inthe direction of the circumference of the condensing portion 11. Theflat plate 11 is divided into two semicircles at two positions of thecircumference thereof; end faces 11 b and 11 c, which are perpendicularto the circumference of the flat plate 11. While the inlet portion 12 isconnected to the end face 11 b of the flat plate 11 so as to communicatewith all of the through holes 11 a, the outlet portion 13 is connectedto the end face 11 c of the flat plate 11 so as to communicate with allof the through holes 11 a.

[0041] As shown in FIG. 4, the inlet portion 12 and outlet portion 13are made from aluminum hollow tubes having closed ends 12 a, 13 a andopen ends 12 b, 13 b, respectively. The slits 12 c, 13 c are formed onthe circumferential surface of the inlet portion 12 and outlet portion13, respectively, and connected to the end faces 11 b, 11 c of the flatplate 11 by brazing. While the open end 12 b of the inlet portion 12 isconnected by brazing to an inflow passage 15 of the refrigerant formedan aluminum tubes, the open end 13 b of the outlet portion 13 isconnected by brazing to an outflow passage 16 of the refrigerant. Thesection area of the outflow passage 16 is smaller than that of theinflow passage 15.

[0042] The clamp 14 is comprised of an insulator 14 c and a band 14 a.The insulator 14 c is formed of polycarbonate thermoplastic resin in asemicircle shape so as to surround the outer periphery of the condensingportion 11. The band 14 a is formed of stainless steel in a cylindricalshape so as to surround the outer surface of the insulator 14 c. Thecondensing portion 11 is inserted into the cylindrical heat absorptionportion 19 and fixed thereto in such a manner that the band 14 a isfastened by inserting a bolt 17 into through holes formed in the bothend portions 14 b of the band 14 a and screwing it by a nut 18.

[0043] The insulator 14 c of synthetics resin is used as it enable toprevent heat of the outside air from being transmitted to the condensingportion 11 and also enables to utilize elasticity of the syntheticsresin in applying uniform radial pressures for fastening the band 14 a.

[0044] In other embodiment, the condensing portion 11 may be formed in acircumferential shape and cut at one portion thereon to form two endfaces, and then either of those two end faces is connected with eitherthe inlet portion 12 or the outlet portion 13.

[0045]FIGS. 5 and 6 shows an evaporator 20, which is comprised of avaporizing portion 21, an inlet portion 22 and an outlet portion 23, andvaporizes the refrigerant by absorbing heat from an exterior heat source29. The vaporizing portion 21 is comprised of a flat aluminum plate witha number of through holes 21 a provided in parallel with each other. Theinlet portion 22 and the outlet portion 23 are formed of hollow aluminumtubes, and have closed ends 22 a, 23 a and open ends 22 b, 23 b,respectively. One end portion 21 b of the vaporizing portion 21 isconnected to the outer surface of the inlet portion 22 by brazing sothat all of the through holes 21 communicate therewith. The other endportion 21 c of the vaporizing portion 21 is connected to the outersurface of the outlet portion 23 by brazing so that all of the throughholes 21 a communicate therewith.

[0046] The open end 22 b of the inlet portion 22 is connected to theinflow passage 25 of the refrigerant by brazing, and the open end 23 bof the outlet portion 23 is connected to the outflow passage 26 of therefrigerant by brazing. The section area of the outflow passage 26 islarger than that of the inflow passage 25. The vaporizing portion 21 isinserted into a head block 24 formed of aluminum, and is screwed on thetop face of the exterior heat source 29 at its through holes 24 a.

[0047] The vaporizing portion 21 and the head block 24 may be integrallyformed into a single-piece member, directly attached on the top face ofthe exterior heat source 29 by means of a cover for example, instead ofthe head block 24.

[0048]FIG. 7 shows an evaporator 30 that vaporizes a liquid refrigerantby absorbing heat from air passing through. The evaporator 30 includes avaporizing portion 31, an inlet portion 32, an outlet portion 33 andfins 34. The vaporizing portion 31 is formed of a aluminum flat platewith a plurality of through holes 31 a arranged in parallel with eachother. And the vaporizing portion 31 is bended at three positions andforms three spaces having rectangular cross section between the flatportions of it. The fins 34 are formed to have wave shapes with thinaluminum plate, and inserted into the spaces contacting with the flatsurfaces of the vaporizing portion 31 at top position of the waveshapes.

[0049] The inlet portion 32 and the outlet portion 33 are aluminumhollow tubes having a closed end 32 a, 33 a and an open end 32 b, 33 brespectively.

[0050] The inlet portion 32 is connected to one lower end portion of thevaporizing portion 31 at its outer circumferential surface. And theinlet portion 32 communicates with all of the through holes 31 a.

[0051] The outlet portion 33 is connected to the other higher endportion of the vaporizing portion 31 at its outer circumferentialsurface. And the outlet portion 33 communicates with all of the throughholes 31 a.

[0052] Then the open end 32 b of the inlet portion 32 is connected to aninflow passage 35 of the refrigerant made from aluminum tube. And theopen end 33 b of the outlet portion 33 is connected to an outflowpassage 36 of the refrigerant made from aluminum tube of which sectionarea is larger than that of the inflow passage 35.

[0053] By employing the above-described configuration, the liquefiedrefrigerant flows into the lower position of the vaporizing portion 31through the inflow passage 35, then gradually vaporizes within thethrough holes 31 a, and finally flow out from the higher position of thevaporizing portion 31 through the outflow passage 36 with larger sectionarea.

[0054] In the above invention, the bending positions of the vaporizingportion 31 are not limited to three positions, but one, tow and morefour bending position are available. And the wave shape of the fin 34 isnot limited U shape, but V shape and other shapes are available.

[0055]FIG. 8 shows a plurality of hollow tubes 41 arranged and fixed inparallel with each other by brazing. Each of the hollow tubes 41 is madeof aluminum and has 1 mm in diameter. By employing those hollow tubes41, either the condensing portion 11 or the vaporizing portion 21, 31may be manufactured in a simpler manner and at a lower cost.

[0056] By applying the condenser 10 and evaporator 20 of the presentinvention to the heat reject portion 51 and heat absorption portion 52in FIG. l0 respectively, a compact cooling device which has highercooling efficiency and easy maintenance is achieved.

[0057] If the condenser 10 is located in an upper position of theevaporator 20 as shown in FIG. l0, the refrigerant can be continuouslycirculated without an external power by the gravity difference betweenthe liquid refrigerant and the vaporized refrigerant. However, if thecondenser 10 is located at an almost same position as the evaporator 20or at a lower position than the evaporator 20, the refrigerant cannot becirculated without a driving pump.

[0058]FIG. 9 shows a driving pump 60 so called “fish tail pump,” whichis known for its compact and simple structure. The driving pump 60 isinstalled in a refrigerant passage 65, and has a sheet spring 61supported at the supporting point 63. As a small piece of metal such asiron is attached on the sheet spring 61, it is vibrated by anelectromagnet 64. Vibration of the sheet spring 61 sends out therefrigerant in such a way that fish moves its tail fin. A small amountof power is enough to send out the refrigerant if the sheet spring 61 isvibrated at its resonance speed.

1. A condenser condensing a refrigerant gas by rejecting heat of saidgas to a predetermined column-like shaped heat absorption portion of anexterior cooling device comprising: a condensing portion; an inletportion; and an outlet portion; said condensing portion formed of a flatplate shaped so as to surround the entire periphery of said column-likeshaped heat absorption portion, said condensing portion further having aplurality of through holes formed along the circumferential directionthereof and arranged in parallel with each other, said inlet and outletportions being hollow tubes having a closed end and an open endrespectively, said inlet portion connected to one end face of saidcondensing portion that is perpendicular to the circumferentialdirection of said condensing portion, said inlet portion communicatingwith all of said through holes, said outlet portion connected to theother end face of said condensing portion that is perpendicular to thecircumferential direction of said condensing portion, said outletportion communicating with all of said through holes, said open end ofsaid inlet portion connected to an inflow passage of said refrigerant,said open end of said outlet portion connected to an outflow passage ofsaid refrigerant which section area is smaller than that of said inflowpassage, said condensing portion inserted into and fixed to saidcolumn-like shaped heat absorption portion.
 2. The condenser of claim 1wherein said condenser is provided with a clamp formed so as to surroundsaid condensing portion, inserted into said column-like shaped heatabsorption portion, and attached to it by fastening said clamp.
 3. Thecondenser of either claim 1 or 2 wherein said condensing portion iscomprised of a plurality of hollow tubes that are arranged in parallelwith each other.
 4. An evaporator vaporizing a liquid refrigerant byabsorbing heat from an exterior heat source comprising: a vaporizingportion; an inlet portion; and an outlet portion; said vaporizingportion formed of a flat plate provided with a plurality of throughholes arranged in parallel with each other, said inlet and outletportions being hollow tubes having a closed end and an open endrespectively, said inlet portion connected to one end portion of saidvaporizing portion at its outer circumferential surface, said inletportion further communicating with all of said through holes, saidoutlet portion connected to the other end portion of said vaporizingportion at its outer circumferential surface, said outlet portionfurther communicating with all of said through holes, said open end ofsaid inlet portion connected to an inflow passage of said refrigerant,said open end of said outlet portion connected to an outflow passage ofsaid refrigerant which section area is larger than that of said inflowpassage, said vaporizing portion attached to said exterior heat source.5. The evaporator vaporizing a liquid refrigerant by absorbing heat fromair passing through comprising: a vaporizing portion; an inlet portion;and an outlet portion; a fin; said vaporizing portion formed of a flatplate provided with a plurality of through holes arranged in parallelwith each other, said vaporizing portion bended to insert a space havingpredetermined height and length between it, said fin inserted into saidspace crossing with said through hole direction, said inlet and outletportions being hollow tubes having a closed end and an open endrespectively, said inlet portion connected to one lower end portion ofsaid vaporizing portion at its outer circumferential surface, said inletportion further communicating with all of said through holes, saidoutlet portion connected to the other higher end portion of saidvaporizing portion at its outer circumferential surface, said outletportion further communicating with all of said through holes, said openend of said inlet portion connected to an inflow passage of saidrefrigerant, said open end of said outlet portion connected to anoutflow passage of said refrigerant which section area is larger thanthat of said inflow passage.
 6. The evaporator of claim 4-5 wherein saidvaporizing portion is formed of a plurality of hollow tubes arranged inparallel with each other.
 7. A cooling device comprising: the condensercited in claim 1, 2, or 3; the evaporator cited in claim 4, 5 or 6;wherein an outflow passage of said condenser is connected to an inflowpassage of said evaporator, and an inflow passage of said condenser isconnected to an outflow passage of said evaporator.